Lapping machine



Filed Aug. ,17, 1940 5 Sheet-Shet 1 Feb. 4, 1941.

w. H. WO OD LAPPING MACHINE Filed Aug. 17, 1940 5 Sheets-Sheet 2 smart/tn! WALL ACE H. WOOD VMLAW mm,

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' LAPPING MACHINE Filed Au 17, 1940 s Sheets-Sheet 4 7 I'll 3mm WAL LACE H. W001:

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LAPPING MACHINE Filed Aug. 17, 1940 5 Sheets-Sheet 5 VI ALLAEE H. W002 ill ' Patented Feb. 4., 1941 Norton Company, Worcester, tion of Massachusetts MBSS-, a COI'POI'EL- Application August 17, 1940, serial No. 353.027

19 Claims.

tion on a work piece. Another object of the invention is to provide an automatically actuated lapping machine for simultaneously lapping a plurality of spaced portions on a work piece.

A further object of the invention is to provide a cylindrical type lapping-machine with a reciprocable type lapping element for lapping the work surface while the work piece is rotated at a progressively increasing work speed in a manner to produce continually varying abrading lines on the surface of the work which are substantially parallel to the work axis at the start of the lapping operation and which are progressively increased in angular relation with the work axis. until they approach a path at-right anglesthereto at the end of the lapping operation. i

Another object of the invention is to provide a lapping machine for lapping a plurality of spaced portions on a rotatable work piece which is semi-automatic in operation and which is conof the invention is to provide a cylindrical type lapping machine in which a plurality of'lapping heads are. automatically moved toward and from a work piece, lapping sticks on each of the heads are automatically started a reciprocating as the heads move toward the work piece, and'in which the work rotation is initiated by the relative approaching movement of the lapping heads.

A further object of the invention is to provide 4 a work driving mechanism which rotates the workat a slow rate of speed at the start of the lapping operation and the speed of which is automatically increased to a maximum at the end 7 the scope of the application of which will be indicated in the following claims. In the accompanying drawings, in wh igh is Another object of trolled, by a single control lever. Another object 7 shown one of various possible embodiments of the mechanicalieatures of the invention- Fig. 1 is a front elevation of a lapping chine embodying this invention;

Fig. 2 is a right-hand end elevation of the lapping machine as shown in Fig. l;

' Fig. 3 is a fragmentary plan view-of the lapping machine; 4

Fig. 4 is a diagrammatic showing of the by: draulic control system;

Fig. 5 is a fragmentary longitudinal sectional view, on an enlarged scale, through the headstock; A

. Fig. 6 is a fragmentary cross-sectional view, taken approximately on the line 6- 6 of Fig. 5, through the headstock;

' Fig. 7 is a fragmentary vertical sectional view; on anenlarged scale, taken approximately on the line 1-1 of Fig. 3, through one of the lapping heads;

v Fig. 8 is a fragmentary vertical sectional view, taken approximately on the line 8-8 of Fig. 7 through .one of the lapping heads;

Fig. 9 is a fragmentary cross-sectional'view, taken approximately on the line 9-9 of Fig. 7, through the lapping head and its support;

Fig. 10 is a fragmentary vertical sectional view,

taken approximately on the line Ill- H] of Figs.

7 and 9; a

Fig. 11 is a fragmentary sectional view, on an enlarged 'scale, taken approximately on the line Il'll of Fig. 1;

Fig. 12 is a fragmentary sectional view, taken approximately on the line |2|2 of Fig. 11;

Fig. 13 is a fragmentary vertical sectional through the gear mechanism for driving the motor operated rheostat for controlling the work 'piece; and V Fig. 14 is a fragmentary sectional view, on an enlarged sectional view through one of the lapping head fluidmotors. I

A lapping machine has been illustrated in the drawings in which a machine base 40 supports a work supporting table 4|. A rotatable work support is, provided on the table 4| including a headstock 42 and a footstock 43. The headstock 42 supports a rotatable headstock spindle 44 in bearings 45 and 46. The headstock spindle 44 is provided with a, suitable driving mechanism such as,' for example, avariable speed electric motor 41. The motor 41 is provided with amultiple V-groove pulley'48 which is drivingly connected 'by multiple v -belts 49 with a multiple V-groove pulley 50. The pulley 50 is fixedly supported on a shaft 5| which is'iourna'lled inbearings 52 and 53 in the headstock 42. A worm 5: is keyed to the shaft 5| and meshes with a worm gear 54 which is;keyed,to the headstock spindle 44.

Work drive A suitable work driving mechanism is provided onthe headstock 42 comprising a slidably mounted drivinghead 55 which is slidably keyed on the headstock spindle 44 (Fig. 5). The right-hand end of thedriver 55 is formed with'a recess 55 which is adap'tedto mate with a flange 51 formed on the end of a work piece, such as a crankshaft 58 to be lapped. Thedriving member 55 is also provided with a spring-pressed driving pin 59 which projects from the recess 58 and is arranged to engage a hole or aperture 58in, the flange 51 of the crankshaft 58. -The work driver 55. is

shown in an inoperative position (Fig. 5) When it is desired to drive and rotate a work piece, the driver 55 is moved toward \the right (Fig. 5) to shift the driving pin 59 into engagement with the hole 58 and to shift the recess 55 into supporting engagement with the flange 51 of the crankshaft 58. A yoke-shaped member 5| is supported by a shaft 52 which is in turn supported by abracket 53 which is formed integral with the headstock 42. The. yoke 5| engages a pair of trunnions 84 and 55 which are formed integral with a semi-circular shaped member 58 which rides in a groove 51 formed in the work driver 55.

The work driver 55 is preferably automatically actuated in timed relation with the other mechanisms of the machine. An arm- 58 is fixedly lower end of a piston 1I.

mounted on the shaft 62. The arm 58 is provided with a yoke-shaped end 59 which straddles and engages a groove 18 formed adjacent to the The-piston 1| is slidably-mounted in a cylinder 12, which is fixed mounted'relative'to the headstock 42. The piston 1| is preferably provided with a central aperture 13. A compression spring 14 is contained within the central aperture 13 and is interposed between the upper end of the aperture 13 and an adjustable stud or stop screw 15 which is fixedly mounted on the headstock 42. The spring 14 normally tends to hold the piston H in .its uppermost position with the work driver in operative driving engagement with the flange 51 on the crankshaft 58 to be lapped.

When the fluid under pressure is admitted through a pipe 15 into a-cylinderchamber 11, a

Footstock ;The other end of the crankshaft 58 is support ed by the footstock 43 which is provided with a footstock center 88.

U a rotatable spindle 8I which is journalled in bearings 82 and 83 within a hollow slidably mounted sleeve 84. .The sleeve 84 is slidably keyed by means of a key 85 within an aperture in the footstock frame 43.

A fluid, pressure actuated mechanism is providedfor moving 'the'footstock center 88 rapidly to and from an operative position, that is, intoor outof supporting engagement with a frusto-conical aperture 88 formed in the rightthe left (Fig. 4)

The center 88 is carried by' hand end of the crankshaft 58. This mechanism comprises a fluid pressure cylinder 81 having a slidably mounted piston 88 contained therein. The piston 88 is connected to one end of a piston rod 89. The other end of the piston rod 89 is provided with an enlarged head 98 having an elongated slot 9| within which slides a slabbed-oif pin 92. The pin 92 serves as a central pivotal connection between a pair of toggle levers '93 and 94, respectively. The toggle lever 94 is connected to the footstock frame 43 by means of astud 95. The other end of the toggle lever 93 is connected by a. stud 95 with a slidably mounted hollow sleeve 91 which slides within an aperture 98 within thesleeve 84. The sleeve 91 is held against rotation by means 01' a screw 99 which is carried by the sleeve 84 and which rides within an elongated slot formed in the sleeve 91. A spring I88 is contained within the sleeve 91 and is interposed between the end of an aperture in the sleeve 91 and a thrust collar MI.

When fiuid under pressure'is admitted through a pipe I82 into a. cylinder chamber I83, the piston 88 is moved downwardly and the toggle levers 93 and 94 are moved from the full line position into the dotted line position 93a and 94a which serves to move the sleeve 91 toward This movement serves to compress the spring I88 and through the connecting parts above .-described moves the sleeve 84 and the footstockcenter 88 into operative engagement with the right-hand end of the crankshaft 58. During this movement fluid is exhausted from a cylinder chamber I84 through a pipe I85. The admission to and exhaust of fluid from the footstock operating cylinder 81 will be. hereinafter described. This footstock is substantially identical with that shown in the prior U. 8. Patent No. 2,117,960 dated May 1'1, 1938, to which reference may be had for details of disclosure not contained herein.

Lapping heads The base 48 is provided with an upwardly extending column H8 which serves as a support fora plurality of lapping heads III, Illa, lb and Hflc. The column H8 is provided with a pair of spaced longitudinally extending T-slots H2 and H3 which serve as guideways adjustably to support the lappin heads III, II Ia, Hi1) and lo. Each of the lapping heads III, III'a, Hlb and IHc is provided with a supporting frame H4, H4a, H417 and H4c, respectively, which is provided with an integral projecting rib H5 which slides within the T-slot H2. The lapping heads I, Illa, IHb, and IHc may be clamped in adjusted position on the column H2 by means of clamping T-bolts H8 and H1. The T-bolts H5 and H1 pass through holes or apertures in the frame H4 and are provided with heads which mate with the T-slots H2 and H3. By means of the clamping T-bolts H6 and H1, the heads III may be adjusted longitudinally in setting up the machine for a. given lapping operation.

Each of the frames or brackets H4 is provided with a forwardly extending portion which serves as a support for a vertically adjustable plate H8. The bracket H4 is provided with a groove H9 in the sliding surface I28 which mates with a correspondingly shaped surface on the plate H8. The plate H8 is provided with a projecting guiding rib I2I which mates with the slot H9 so as'to guide theplate H8 in avertical direction. The plate may be clampedin adjusted position on the bracket H4 by means of clamping screws I22 and I 23. which pass through elongated slots I25 and I25 in the bracket H5 and are screw threaded into the A vertically arranged adjusting plate II8. Y screw I25 is carried by a boss I21 (Fig. formed integral with the bracket H5 and serves to facilitate vertical adjustment of plate I I8. The plate H8 serves as a support for atransverselyadjustable bracket I30. The plate I I8 is providedwith a groove I3I which is engaged ,"by arib I32 formed integral with the bracket- I30. -Clamping screws I33 and I35 are passed through elongated slots I35 and I20, respectively, and are screw threaded into the plate H8 and serve to facilitate a transverse adjustment of the bracket I30. i

liiydraulic lift-Lapping heads In order to facilitate loading of work pieces. into the machine and removal .thereof after a lapping operation has been completed, it is delowering the lapping heads III, In, lb and IIIc to and from an operative position. This is preferably accomplished by means of a fluid pressure mechanism such as, for example, an individual fluid pressure piston and cylinder as 3o sociated with each of the lapping heads. A fluid pressure cylinder I40 is formed integral with the bracket I30. The side face of the cylinder M0 is provided with a dovetailed guideway MI which mates with a correspondinglyshaped way 5 formed on the lapping. head III (Fig. 9). A piston I52 is slidably mounted in the cylinder I50 and is connected to one end of a piston rod 153. connected to a plate I44 mounted on the'upper 40 end of the lapping head I-II (Fig. 8). This rais-" ing and lowering mechanism for the lapping heads is identical, consequently details of each of the mechanisms have not been shown in the drawings although they have all been indicated in the hydraulic diagram shown in Fig. 4, like .parts of each of the mechanisms being desig- -nated by the same numerals with the suflix a, b,

.. or c.

It will bereadily apparent from the foregoing to disclosure that when fluid under pressure is admitted through a pipe I45, I45a, 145b, and 50 to the cylinder chambersabove the pistons I42, I42a,

' M26 and I420 (Fig; 4) ,'a downwardmovement of no passed through the pipes 146. I450, I48!) and Y I460, the pistons I42 will be moved upwardly simultaneously to raise all of the lapping heads III, IIIa, lb and lo to an inoperative or loading position. ,The hydraulic system for con- 05 trolling the admission of fluid under pressure through the pipes I45 and I40 will be hereinafter described. Each of the lapping leads I II is provided with a lapping element preferably comprising a stickpi bondedabrasive material such 70 as, for example, the lapping sticks I50 and I5I '(Fig. '7). Thelappingsticks I50 and I5I are supported on a lapp n stick holder I52 which is provided with'oppositely extending trunnions I53 and I54 which; are in'turn pivotally sup- "75 ported in bearingscarried by theside plates I55 The upper end of the piston rod I43 is and I56. The plates I55 and I56 are supported on an oscillatable arm I51 which is arranged to oscillate about the axisof the stud I58'as a pivot.

Lapping stick-Straight Zine motion 5 In order that a straight line motion may be imparted to the lapping sticks I50 and I5I, a slight vertical movement of the oscillatable arm I 51 and its supporting stud I58 is provided. A 10 pair of spaced slides I59 and IE0 are mounted on opposite ends of the stud I58 and are arranged to slide in parallel guide surfaces m and I52, respectively. The upper end of the oscillatable arm I51. carries a roller I63 which is mounted on 15 a stud I54. The stud-I64 is fixedly mounted on the oscillatable arm I51 and supports the roller I53 so that it engages a cam face I55 which is flxedlysupported relativeto the plate I04. The

. shape of the cam I65 is such that when the oscilg0 latable arm I51 is oscillated, it will impart a straight line reciprocatory movement of the lapping sticks I50 and I5I. The roller I63 is normally held in operative engagement with the cam I 55 by means of the fluid under pressure within 5 the cylinders I40. A spring I68 is fastened at its upper end to the oscillatable arm I51 and at its lower end to an adjustably positioned stud I 81 and serves to exert a downward force on the oscillatable arm I51 yieldably to maintain the lapping sticks I50 and I5I in operative lappingi em gagement with the work piece being lapped; A stop pin I58 carried by the lapping head iIII serves to limit the downward movement of the oscillatable arm I51. The stop stud I08 is arrangedin the path of the pivot stud I58.

Fluid motor-Lapping stick reciprocation .A suitabl power operated mechanism is provided for oscillating the arm I51 to reciprocate the lapping sticks I50 and I5I in operative engagement with the work piece to lap the same.

In the preferred form, aself-contained fluid pressure motor" is provided comprising a fluid pressure motor I10, I10a, Oh and I10c is provided on each of the lapping heads III, IIIa, IIIb and lo, respectively. Each of these mo-, tors comprises a cylinder I1I (Fig-14) having a piston I12 slidably mounted therein. The piston I12 is connected by means of a piston rod I13 with the upper end of the oscillatable arm I51. A pilot valve I14 is slidably mounted within the motor casing I10. The 'pivot valve I14 is provided with a central bore or aperture which contains a slidably mounted shuttle type reversing valve I15. The pilot valve I14 is provided with a pair of adjustable collars I16 and I11 which are engaged by an upwardly extending portion of the oscillatable lever I51 by means of which the pilot valve is automatically shifted at .the end of the 6 table stroke to shift the reversing valve and thus change the direction of oscillation of the lever I51 continuously to reciprocatethe lapping sticks I50 and .I5I. Fluid under pressure is admitted through a pip I18 into the valve mechanism to 5 actuate the piston I12 as desired. An exhaust pipe I19 is provided whereby fluid is readily exhausted from the fluid motor. The collars I16 and- I 11 are preferably adjustably mounted on the valve stem so that the length of the oscillatory stroke of the arm I51 and also the reciprocatory stroke of the lapping sticks I50 and I5I,=respectively, may be adjusted 4 as desired. This hydraulic motor hasmgt been described in detail I in the present application, since the details of the 'flled October 29, 1938.

tive position, the cams will engage the rollers I90 androck the shaft present invention. Any standard motor, either hydraulic or otherwise, might be employed for this purpose. For details of disclosure not contained herein, reference may be had to my pending U. S. patent application Serial No. 237,654,

It is desirable automatically to start the reciprocatory movement of the lapping sticks I50 and l5l 'when the lapping head III is moved toward an operative position and similarly to stop the reciprocation thereof when the lapping head is moved to an inoperative position. To accomplish this desired result, a normally closed valve I is provided for each of the,motors I10 in the pipe lines I18, I18a, I18b and I18c. The

valve I80 may be opened by means of.a pivotally mounted lever I8I having an actuating roller I82 at its lower end. In order that the valve may be automatically controlled by the approaching and receding movement of the lapping head I I I, a cam I83 is adjustably'mounted on the bracket I30 which supports the lapping head III. A'pair of screws which hold the cam I83 in adjusted position on the bracket'l30 pass through elongated slots in the bracket, thus facilitating a slight transverse adjustment of the bracket to adjust the time of opening the valve I80. This adjustment is intended for use in setting up the machine to facilitate starting reciprocatory movement of all. the heads at the same time. Each of the lapping heads III is provided with a similar construction and the corresponding parts are identified by the same reference numerals suflixed with the designations a, b, and c.

In order that the cycle of operation of the machine may be automatic it is desirable to provide an automatically actuated mechanism for starting the rotation of the work drive motor 41 in timed relation with the other parts of the machine. In the preferred form, it is desirable to start the rotation of the motor 41 when the lapping heads III are moved toward an operative position and similarly to stop the work drive motor when the heads are moved to an inoperative or loading position. A rock shaft I85 is supported.

at one end in a bearing I81 which is formed integral with the plate "80. An intermediate bearing I88 is formed integral with the plate I I8, thus A..pair of clamping. screws pass through elongated slots in the cam I9I and are screw threaded into the lapping head III.. Cams I9Ia, I9Ib and I9Ic are adjustably' mounted on lapping heads Illa, IIIb and I0, respectively. A downwardly extending arm I92 is mounted on the right-hand end of the rock shaft I85. A link I93 connects'the arm I92 with the actuating lever I94'of a normally open limit switch I95. It will be readily apparent from the foregoing disclosure that when the heads III, Illa, lb and IIIc are moved downwardly into an opera- I9I, I9Ia, I9Ib and I9Ic I85 in a counterclockwise direction (Fig. 4) which in turn serves to rock the lever I94 of the limit switch I95 in a clockwise direction (Fig. 4) to close the switch I95. The switch I95 is operatively connected in a manner to be hereinafter described to start rotation of the work driving motor 41. The cams I9I, I9Ia, I9Ib and I9Ic are preferably adjusted in a vertical direction so that they all engage their respective rollers I at substantially the same time.

It will, however, be readily apparent from the foregoing disclosure that the first cam I9I engaging the roller I90 serves to start a rocking movement of the rock shaft I85 on the downward movement of the lapping heads II I to start closing the limit switch I95. ,Similarly, it will be readily apparent that as the lapping heads I I I last cam I9I to leave the roller I90 serves to allow the rock shaft I85 to be rocked to an inoperative position to again. open the limit switch I and thereby stop the rotation of the work move upwardly to an inoperative position, the

at the end of a lapping cycle. An arm- I98 is .tension of the spring I91 serves to rock the rock shaft I85 in a clockwise direction so as to aid in opening thenormally open limit switch I95, thus stopping the work driving motor 41.

Hydraulic system A hydraulic or fluid pressure system is provided for supplying fluid under pressure to the various mechanism of the machine. A fluid reservoir 200 is provided in the base of the machine. A motor driven fluid pressure pump 20I serves to pump fluid through a pipe 202 from the reservoir 200 and forces fluid under pressure through a pipe 203. Fluid under pressure in the pipe 203 passes through-a pipe 204 to a manually operable main control valve 205 to be hereinafter described and also passes fluid under'pressure through a pipe 206 to a progressively actuated, automatically controlled valve 201 which will also be hereinafter described. Fluid under pressure in the pipe 208 also passes through a pipe 208 which is connected with the pipes I18, I18a, H81: and I to supply fluid under pressure to operate the hydraulic motors I10, I10a, H017 and I100. Fluid under pressure exhausting from the motors I10, I10a, I10?) and H00 passes -through a pipe 209 whichexhausts-into the reservoir 200.

The progressively actuated control valve 201 is a piston type valve comprising a valve stem 2I0 having valve pistons 2I I, 2I2, 2I3 and 2I4 formed integral therewith. The valve pistons 2| I,,2I2, 2I3 and 2I4, form valve chambers 2I5, 2I6, 2I1, 248 and 2 I9. The progressive valve 201 serves to control the admission of fluid under pressure to the cylinders for raising and lowering the lapping heads III, to the cylinder for actuating the fodtstock center 80 and also to the cylinder 12 for actuating the work driver 55. In the position of the valve 201 (Fig. 4), fluid under pressure passing through-pipe 206 enters the valve chamber. 2" and passes outwardly through a pipe 220 which connects withthe pipes I48, I48a, I46!) and I460 to admit fluid under pressure to the cylinder I40, I40a, I40b and We to raise all of the pistons I42 and the lapping heads III to an uppermost or inoperative position. During this movement, fluid exhausting from the cylina pipe 23!.

passes outwardly into a valve passage 222 and -'the pistn.88, thus shifting the footstock parts the work driving member 55 toward the left to an inoperative or leading position. During the upward movement of the footstock piston 89, fluid within the cylinder chamber I03 exhausts through the pipe I02 into the valve chamber 2 l6 and out through the valve passage 222, pipe 223, and the pipe 209 into the reservoir 200.

The main control valve 205 is preferably a piston type valve comprising the valve pistons 226, 22! and 222 forming valve chambers 229 and 230. In the position of the valve 205 (Fig. 4),

fluid under pressure in the pipe 204 enters the valve chamber 230 and passes outwardly through chamber 215 of the valve 201 which serves to move the valve stem 2l0 toward the right (Fig.

4) into the position as illustrated. This position is at the end of thelapping cycle when the parts of the machine are in a loading position. During the movement of the valve stem 2T0 to- I ward the right, fluid within the end chamber 2l9 on the lower end of the valve.

exhausts through a pipe 232 into the valve chamber 229 in the valve 205 and passes into the valve passage 233 and out through a pipe 234 which connects with the exhaust pipe 209 to exhaust fluid into the reservoir 200. The valve 205 is Amanually operable control lever 238 is pivotally supported by means of a stud 239 on the front of the machine base 44. The stud or rock shaft 239 is mounted in a suitable bearing 240 formed in an apron 24| which is fixedly sup rted on the base 40 of the machine.- A downwardly projecting lever 242 is fixedly mounted on the inner end of the shaft 239 (Fig.'11). The downwardly extending arm 242 carries a stud 243 which is connected to the upper end of a link 244. The lower end of the link 244 is connected by a stud 245 with the upper end of the valve piston 226. It

will be readily apparentfrom the foregoing disclosure (Fig. 4) that the arm 242 and link 244 serve. as toggledevers for actuating the valve 205.

When it is desired to start a lapping cycle, the

lever 238 is moved in a counterclockwise direction into position 238a (Fig. 4), which movement rocks the arm 242 into position 242a and the link 244 into position 244a, thus causing a downward movement of the valve pistons 226, 221 and 228.

In the downward position of the valve 205, fluid under pressure from the pipe 204 enters the valve chamber 229 and passes outwardly through the; pipe 232 into the end chamber 2l9 to shift the valve stem 2l0 toward the left (Fig. 4)

Movement of the valve stem 2) toward the left serves first to uncover the pipe l02so that- The pipe 23! is connected to an ,end

fluid under pressure within the valve chamber 2|! passes throughthe pipe 402 into the cylinder chamber I03 to cause a downward movement of the footstock piston 88, thus operating to move the foots'tock center 80 into operative engagement with the cone-shaped aperture at the right-hand end of the work piece 58. At the same time, the valve piston 2l3 has moved a sufficient distance toward the left so that fluid within the chamber" ll of the cylinder 12 may-exhaust through the pipes 16 and 225 into the valve chamber 2 l8 and out through the passage 222, the pipe 223, and exhaust pipe 209 into the reservoir 200. Exhausting of fluid from the cylinder chamber ll releases the compression of the spring 14 which serves to rock the shaft 62 and the yoke 6| to move the work driven 55 toward the right (Fig. tinto operative engagement, with the driving pin 59 and the recess 56 in operative supporting en-E gageinent with theflange 51 on'the left-hand end of .the work piece 58. If the pin 59 does not engage the aperture 30 in the flange 51', the spring back of the drive pin59 will be compressed and when the headstock spindle 44 starts rotation, the driving pin 59 will drop into the hole 30 on the first rotation of the work driver head '55, thus drivingly engaging and driving the work piece 58.

When the control lever 238 is rocked in a counterclockwise direction to actuate the valve 205, the downwardly extending arm 242 and the link 244 move just past a straight line position with a downwardlyextending projection 246 on the arm 242 engaging the left-hand side face of the link 244 (Fig. 12) which serves as a stop to limit the movement of the lever 233 and thereby serves to lock the arm 242 and the link 244 against the compression of the spring 235. As the control lever 238 and shaft 239 are swung in a counterclockwise direction-to actuate the valve 205 to initiate a lapping cycle, a downwardlyextendlng arm 247 formed integral with' the lever 239 engages an actuating plunger 248 of a normally open limit switch 249., The normally open limit switch 2491s electrically connected to cooperate with the normally open limit switch 495 to aid in starting the 'work drive motor 41, the electrical circuit being arranged so that the work ,drive motor 41 is not starteduntil both of the limit switches 249 and I95are closed.

In order automatically to stop the lapping cycle after it-has progressed to a predetermined extent, an electric solenoid 250 i operatively con-, nected by means of a link 25! witha stud 252 carried by the arm 241. At the end of the lapping cycle, energization of the solenoid 250 serves to move the link 25| toward the left (Fig. 4), which breaking 'of the-toggleconnection servesto withdraw the arm 241 from' engagement with the plunger 248 of the limit switch 249, thus allowing the limit switch to open, which through an electrical circuit serves to stop the work drive motor 41. y

Iaterloclc It is desirable that the various mechanisms of.

the machine as above described have suflicient time to function before the next succeeding mechanism operates. It is, therefore, desirable to provide an interlocking of the various mechanisms of the machine whichmay comprise a series of;

Patent No. 2,166,085 dated July 11, 1939'.

stops which serve to limit the movement of the progressive control valve 291 when it is moved in either direction. These stops are interconnected with the various mechanisms so that after 5 a mechanism has performed its function, the

- valve stop will be automatically withdrawn, thereby permitting a further movement of the progres-- .sive control valve 201. This mechanism is somewhat similar to that disclosed in my prior '0'. S.

A stop collar'255 is flxediy mountedonfth rear end of the valve stem 2). The collar 255 is arranged to slide within an aperture formed within a casing 254 which is fixedly mounted on the rear end of the casing of the valve 281. The

casing 254 serves as a support for a plurality of spring-pressed stop plungers which are arranged intermittently to stop the movement of the valve stem 2 II) when it is moved either toward the rear 0 after a lapping operaticn has beenoompleted or when the valve is moved forward after a new work piece has been loaded into the machine to start a lapping operation. As shown in Fig. 4, the valve 281 together with the other mechanisms of the machine are shown in a loading position.

.A stop plunger 256' is normally held in an operative position in the path of the stop collar 255 on the valvestem 2) by means of a spring 251.

' The stop 256 serves to stop the movement of the progressive control valve 201 when it is moved in a direction toward the left (Fig. 4). A similar stop plunger 258 is slidably supported in the casing 254 and is normally held in an operative position in the path of the stop collar 255 by means of a spring 259.

The stop plunger 256 is connected by a link 260 with one end of a flexible cable, commonly known as a Bowden wire 26I. The other end of the Bowden wire 26I is connected by means of a 40 stud 262 which is fixedly mounted on one arm of the yoked end 69 of the lever 68 which actur ates the work driver 55. When the machine isin a loading position, fluid under pressure passing through the pipe 16 (Fig. 4) normally holds the piston H in a downward position which,

through the Bowden wire 26I, serves to hold the stop plunger 256 in an operative position in the path of the stop collar 255 -so that when the valve stem 2I8 is moved toward the left (Fig. 4),

it will move only until the collar 255 engages the stop plunger 256. During the movement of the valve stem 2IIl toward the left, the valve piston 2I3 opens the pipe 225' to the exhaust pipe line to exhaust fluid from the chamber I04 of the footstock cylinder 81 and at the same time to exhaust-fluid from the cylinder chamber 11 in the work drivecontrol cylinder 12. When fluid in the chamber 11 is open to-the exhaust line, the released compression of the spring 14 serves to cause an upward movement of the piston H and at the same time an upward pull on the headstock end ofthe- Bowden wire 26I, which move merit serves tocause a. downward movement of the stop plunger 256, thus facilitating a further I movement of the valve stem 2III toward the-left (Fig; 4). It will be readily apparent'from the foregoing disclosure that the stop plunger 256 serves as an interlock to prevent admission of fluid under pressure to move the lapping head IILto an operative position until the fo otstock center has been moved into'operative supporting-engagementwitnthe work piece 58 and the work driver 55 also moved into an operative position. 4

" Similarly, thestop plunger 25a is provided to movement toward the right so as to interlock the movement of the lapping heads I I I and the footstock' center 80 so that the footstock center 80 cannot be withdnawn until the lapping heads III have been moved upwardly to an inoperative'position. The stop plunger 258 is connected .by a link chain 263'with one end'of a rock arm 264 which is in turn pivotally supported by a stud 265. The stud 1265 is fixedly supported on the casing 254. A tension spring 266 is connected between one end of the rock arm 264 and a stud 261,carried by the casing 254 and serves to exert a pressure normally tending to hold the stop plunger 258 in operative position in the path of the stopcollar 255. The other end of the rock arm 254 is connected by means of a Bowden wire 2'68. The other end of the Bowden wire 268 is wire 268 sons to rock the rock arm 264 in a counterclockwise direction so that the released compression of the spring 259 moves the stop plunger 258 into an operative position in the path of the stop collar 2'55. In this position, when the valve stem 2 I0 is moved toward the right from its extreme left-bland position, the stop plunger 258 will prevent further movement of the valve stem 2 I II toward the right until all of the lapping heads I II have been raised to an inoperative position and the rock shaft I rocked in a clockwise direction by released compression of the. spring I91 (Fig. 1) which movemenrt serves to exert a pull on the Bowden wire 268 to withdraw the stop plunger 258. It will be readily apparent that .the stop plunger 258 stops the valve stem 2 I 0 in a position to prevent admission of fluid under pressure to the pipe 225, to the footstock cylinder 81 and the headstock work driver cylinder 12 to move them to an inoperative or a loading position until all of the lapping heads III have moved .to an inoperative P position.

In order to produce a cylindrical surface of the desired quality, it is desirable'to provide a variable speed work driving mechanism by which the anism from the start of the operation is progressively and continuously increased while the speed I of reciprocation of the lapping sticks remains constant so that the path of movement of individual grains in the lapping sticks progressively and continuously changes from a path substantially parallel to the axis to a final path at substantially right angles thereto.

In the preferred construction, the work driving motor 41 is preferably controlled by an automatically actuated rheostat mechanism such as, for example, by a motor driven or operated rheostat such as, for example, the motor operated switches, CR8 490 manufactured by the General Electric Company. The motor operated switch unit comprises a rheostat member 210 which is provided with an actuating arm which is provided with a rotatable control arm 21I which is in turn automatically rotated by means of a variable speed electric motor 213. The electric motor 213 is connected by a reduction gear mechanism. The motor 213 is provided with a motor shaft 214 having formed integrally therewith a worm 215 which meshes with a worm gear 216. The worm gear 215 is rotatably supported ona stud 211 which is fixedly supportedon a frame 218 which is supported on the rear of the column III] of the machine. A small gear 219 is also rotatably supported on the stud 211 and is fixedly keyed to the worm 218. The gear 219 meshes with a large gear 289 which is rotatably mounted on a stud 28I. The stud 28I is fixedly mounted on the frame 218. The stud 28I also supports a, gear 282' which is arranged to rotate with the gear 289. The gear 282 meshes with a gear 283 which is supported on the rheostat control shaft 284. The motor operated rheostat switch 218 is connected to control the rotation of the work driving motor 41 so that at the first of thelapping cycle, the rotation of the work piece 58 will be at a relatively slow speed, which speed will be continuously and progressively increased until the work sp'eed reaches a maximum at the end of the lapping cycle.

"The speed of the motor 213 for driving the rheostat 219 is manually adjustable so that the cycle sired, thus providing a manual control for adjust--v ing the duration of the lapping cycle.

The motor operated rheostat switch unit 210 is of an automatic reset. type in which the variable speed reversible motor 213 rotates in one direction during the lapping operation and which is automatically reversed and rotated in the re verse direction after a lapping cycle has been completed tofreset the rheostatfor the next lapping operation. This motor driven rheostat is a standard unit manufactured by the General Elec tric Company and, therefore, it is not deemed necessary to illustrate the details of this motor driven rheostat switch.

Apush button switch 290 is provided on the front of the machine base 40 for starting and stopping the fluid pressure pump motor 29I. A pushbutton switch 292 is also provided'on the front of the machine base 40 for rendering the circuitcontrolling the workdriving motor 51 oner-ative.

A pair of 'work supporting or loading brackets 295- and 296 are provided on the table M'for supporting a crankshaft .58 to be ground. These loadingbrackets comprise horizontally positioned surfaces whereby the crankshaft 58 may be positioned and rolled into alignment with the work driver and the footstock center 80.

The operation of this machine will be readily apparent from the foregoing disclosure. Assuming the various'mechanisms of the machine to have been previously adjusted, a crankshaft to be The work piece, such as the crankshaft 58, is then moved transversely into axial alignment with the work driver 55 and the footstock center 80. The control lever 238 (Fig. 1) is then moved me counterclockwise direction, which movement shifts the valve 205 downwardly. This movement of the control lever closes -the limit switch 229 and at the same time admits fluid under pressure through the pipe 232 into the right-hand end chamber 2I9 of the valve201 to shift the pro gressive control valve 291 so as to start the lapping cycle.

During the first part of the movement of the valve 201 toward the left (Fig. 4), fluid under pressure is admitted to the cylinder chamber I03 of the footstock actuated cylinder and also to the chamber 11 of the headstock work driver cylinder 42 simultaneously. to move the work driver 55 and the footstock center'Bfl into operative supporting engagement with the opposite ends of the crankshaft 58. The downward movementof the piston 11 in the headstock cylinder 42 serves to.

draw the stop plunger 256, thus allowing the progressive control valve to complete its movement toward the left (Fig. 4), which movement serves to admit fluid under pressure to the cylinder chamber above the pistons I42, M2a, I42!) and I420 to cause a downward movement of the pistons so as to move the lapping heads III, IIIa,

I I Ib and I I I0 downwardly into an operative posi-' tion with the lapping sticks I 58 and, I 5| in operative engagement with the spaced portions of the shaft to be'lapped. During the downward movement of the lapping heads II I, the cams I9 I, I9Ia, I9Ib and I9Ic engage rollers I99, I9Ila, E9021 and I900. The first cam to engage its respective roller rocks the shaft I85, thus closing the normally open limit switch I95 which starts the rotation of the work driving motor 51 at aslow rate of speed. The downward movement of the lapping heads III, IIIa, III!) and I0 also serves through the rollers I82, I82a, I82b and I820 moving into engagement with the cams I83, I83a, I831), and l83c.to open the valves I89, I89a, Nb and I800, respectively. The. opening of these valves serves to admit fluid under pressure to the fluid motors I10, IIIla, I19!) and I10c' simultaneously to produce a reciprocatory movement of all of the lapping sticks.

As the lapping operation proceeds, the speed of the driving motor 81, under the control of the motor driven rheostat 219 is gradually and progressively increased to gradually and progressively increase the speed of rotation of the crankshaft 58. At the start of the lapping operation, the lines of travel of the individual abrasive grains as produced by the combined reciprocatory stroke of the lapping sticks and the rotation of the work piece 51 produces lines orr'the work piece which are substantially parallel to the axis of rotation of the shaft 58. As the speed of the work piece 58 is gradually'and progressively increased, these lines produced by individual abrasive grains of the lapping sticks gradually change their direction until at the end of the lapping cycle, these lines approach a pathnormal tothe axis of rotation of the shaft. This gradual increase of speed provides an /ever changing path of the abrasive grains in the lapping sticks, thus J providing a complete break-up .motion of the abrading action of the sticks to produce an ultradfine finish on the periphery of the work piece be -ing lapped.

After. the motor driven rheostat has completed .its cycle and brought the .work drive motor 41 up to the maximum speed, the lapping operation is stopped. The solenoid 250 is energized which breaks the toggle action between the levers 242 which serves to stop the lapping cycle.

and 244 again shifting the valve 205 upwardly to admit fluid under pressure through the pipe 23l into the cylinder chamber 215 at the lefthand end" of the progressive control valve 201 The valve 201 can only move until the stop collar 255 engages the stop plunger 258. This movement of the valve serves to admit fluid to the cylinder chamber below the pistons I42, l42a, 2b and M20 to cause an upward movement of all of the lapping heads to their inoperative position. Upward movement of the lapping heads serves to close all of the valves I80 to stop the reciprocatory movement of the lapping sticks. lapping head has moved upwardly so that all of the cams l9l have withdrawn from contact with the rollers I90, the released compression of the spring I91 willrock the shaft I85 in a clockwise direction (Fig. 4) to. withdraw the stop plunger 258, thus allowing the progressive control valve 201 to complete its movement toward the right (Fig. 4).

This final movement of the valve 201 serves to admit fluid under pressure through the pipe 225 the footstock center 80 to an inoperative position and at the same time fluid under pressure is admitted to the headstock cylinder 1''! to cause a downward movement of the piston II which inturn serves to withdraw the work driver 55 to an inoperative .position so that the'work piece 58 which has been lapped may be readily removed from the machine and replaced by a new piece to be lapped. This cycle of operation may then be continued. It should be noted that the cycle of operation is semi-automatic in operation, it being merely necessary for the operator to start the cycle by shifting the control lever 238, after which the various mechanism of .the machine automaticallygo through their cycle of operation until the shaft has been lapped, after which the cycle is automatically stopped.

It will thus 'be seen that there has been provided .by this invention apparatus in which .the

various objects hereinabove set forth together with manythoroughly practical advantages are successfully achieved. As many possible em- 'bodim'ents' may be made of the above invention and as many changes might be made'in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the-accompanying drawings is to be inter- I preted as illustrative and not in a limiting sense.

Iclaimz- .L-In "a? lapping machine having -'a rotatable work support, a work driving mechanism to rotate a ,work piece supported thereon, a lapping head including a reciprocable lapping element,

means including a motor to reciprocate said lapping element, means to stop and start said motor,

means including a motor to move said head to and from an operative position, means including a control lever to control said latter motor, and

reciprocating motor and to'start ing mechanism. I

2. In a lapping machine having a .rotatabl work support,. a work driving motor to rotate a 'means actuated by movement of said-head to an operative position to start said lapping element said work drivwork piece supportedthereon, a lapping head including a reciprocable lapping element, means including a motor to reciprocate said 1' pping ele- After the last ment, means to stop and start said motor, means including a motor to move said head to and from an operative positiommeans including a control lever to controlsaid latter motor, and means actuated by movement of said head to an operative position to start said lapping element reciprocating motor and to start said work driving motor.

3. In a lapping machine having a rotatable work support, means to rotate a work piece supported thereon, a lapping head including a reciprocable lapping element, means including a motor to reciprocate said lapping element, means to start and stop said motor, means including a motor .to move said head to and from an operative position, means including a control lever to co'ntrol said latter motor, means actuated by movement of said head to an operative position to start said lapping element reciprocating motor,

and means actuated by movement of said head to an operative position to start said work driving mechanism.

4. In a lapping machine having a rotatable work support, means including an electric motor to rotate a work piece supported .thereon, a lapping head including a reciprocable lapping ele ment, means including a fluid motor on said head to reciprocate said lapping element, a stop and start valve to control said fluid motor, means including a fluid pressure piston and cylinder to .move said head to and from 'an operative position, acontrol lever and valve to control said piston and cylinder, means including a cam actuated by movement of .the head toward an oper-ative position to actuate the stop and startciprocate said lapping element, means to stop and start said motor, means including a motor to move said head to .and from an operative position, means including a control lever to control said latter motor, means actuated by movement speed at the start of the lapping cperationto a maximum speed at the completion. of a lapping cycle, a lapping head including a reciprocable lapping element, means including amotor on said head to reciprocate said lapping element,

means to move said head toward and from an -operative position, and/means actuated by and in timed relation with movement of the head to,

an'operative position to start said fluid motor so as to reciprocate the lapping elementand to start said rheostat and thereby start the work drive motor to rotate the work piece.

7. In a lapping machine having Jo rotatable work support, means including a variable speed electric motor to rotate a work piece, a motor ative position to start said fluid motor sons to I reciprocate the lapping element and to start said rheostat and thereby start the work drive motor to rotate the work piece.

8. In a lapping machine having a rotatable work support; means including a variable speed electric motor to rotate a work piece supported thereon, a motor driven variable speed rheostat to control said motor, a lapping head including a reciprocable lapping element, means including a fluid motor on said head to reciprocate' said lapping element, a fluid pressure operated piston and cylinder to move said head toward and from an operative position, and means actuated by and in timed relation with movement of the head to an operative position to start said fluid motor so as to reciprocate the lapping element and to start said rheostat and thereby start the Work drive motor to rotate the work piece, said rheostat serving to start the work drive motor at a relatively slow speed and automatically and progressively to increase the work speed as the lapping operation proceeds.

9. In a lapping machine having a rotatable work support, means including an electric motor to rotate a, work piece supported thereon, a plurality of spaced lapping heads arranged simultaneously to lap spaced portions on a cylindrical workpiece, a reciprocable lapping element on each head, a fluid motor on each head to reciprocate the lapping element, a start and stop valve on each head to control said motor, means including an independent piston and cylinder to move each head to and from an operative position, an independent adjustably mounted cam associated with each head to open and close the start and stop valve when the heads are moved to and" from an operative position so as to control the reciprocation of said lapping elements, and a manually operable control valve simultaneously to control the admission to and exhaust from each of the lapping head moving cylinders.

10. In a lapping machine as set forth in claim 9, the combination with the parts and features therein specified, of means including a limit switch to start the work drive motor, means including a rock shaft to actuate said limit switch,

- and means including an adjustably mounted cam on each lapping head which are arranged to rock said shaft to close said switch and start the work drive motor when the heads are moved to an operative position.

11. In a lapping machine as set forth in claim 9, the combination with the parts and features drive motor when the heads are moved to an operative position; said parts being arranged so that the first cam to rock said shaft serves to start the work drive motor.

- 12. In a lapping machine as set forth in claim 9, the combination with the parts and features therein specified, of means including a normally open limit switch to start the work drive motor, means including a rock shaft to actuate said limit switch, a spring normally to hold said shaft to maintain said switch open, and means including 'an adjustable cam on each lapping head which are arranged to rock said shaft to close said switch and start the work drive motor when the heads are moved tov an operative position.

13. In a lapping machine as set forth in claim 9, the combination with the parts and features therein specified, of means including a normally open limit switch to start the work drive motor, means including a rock shaft to actuate said limit switch, a spring normally to hold said shaft to maintain said switch open, and means including an adjustable cam on each lapping head which are arranged to rock said shaft to close said switch and start the work drive motor when the heads are moved to an operative position, said parts being arranged so that the movement of the last head to an inoperative positive position serves to release the tension of said spring to rock the shaft and open the limit switch so as to stop the work drive motor.

14. In a, lapping machine having a base, a rotatable work support thereon including a headstock having a work driver and a footstock having a center, a fluid motor to move said work driver to and from an operative position, a fluid motor to move said footstock center' to and from an operative position, means including an electric motor to rotate said Work driver, a lapping head having a reciprocable lapping element, means including a fluid motor on said head to reciprocate said lapping element, means including a fluid motor to move said lapping head to and from an operative position, means including a switch actuated'by and in timed relation with movement of said lapping head to an operative 14, the combination with the parts and features therein specified, of a manually operable cycle valve, a fluid pressure actuated, progressively moved valve, said latter valve being arranged to control the admission of fluid under pressure to the work driver fiuid motor, the footstock center fluid motor and the lapping head positioning motor,-and a stop to limit the movement of the progressive valve in one direction to prevent ad-- mission'of fluid under pressure to the work driver and footstock fluid motors until the lapping head is in an operative position.

16. In a lapping machine as set forth in claim 14, the combination with the parts and features therein specified, of a manually operable cycle valve, a fluid pressure actuated, progressively moved valve, said latter valve being arranged to control the admission of fluid under pressure to the work driver fluid motor, the footstock center fluidmotor and the lapping head positioning motor, a stop to limit movement of the progressive valve in one direction, and means actuated by movement of said lapping head to an inoperative position to withdraw said stop, thereby preventing withdrawal of the work driver and footstock center until the lapping head is moved to an inoperative position.

1'7. Ina lapping machine as set forth in claim 14, the combination with the parts-and features therein specified, of a manually operable cycle valve, a fluid pressure actuated, progressively moved valve, said latter valve being arranged to control the admission of fluid under pressure to ,14, the combination with the. parts and features therein specified, of a manually operable cycle valve, a fluid pressureactuated, progressively moved valve, said latter valve being arranged to control the admission of fluid under pressure to the work driver fluid motor, the footstock center fluid motor and the lapping head positioning motor, a stop to limit the movement of the progressive valve in one direction, and means actuated by movement of the work driver into an operative position to withdraw said stop, thereby preventing movement ofthe lapping head toward an operative position until the work driver and footstock center are in an operative position.

19. In a lapping machine as set forth in claim 14, the combination with the parts and features therein specified, of a variable speed electric motor to rotate the work driver, a motor driven variable speed rheostat to control said motor,

'said rheostat serving to start the work drive motor at a relatively slow speed and automatically and progressively to increase the work speed to a maximurnat the end of a lapping cycle, and means including a solenoid'which is actuated when the work reaches its maximum speed to shift the manually operable control valve to terminate a lapping cycle. I

WALLACE H. WOOD. 

